Abstract
The distribution of total and free amino acids in the TCA soluble fraction was studied in the course of natto manufacture, by means of paper-and ion-exchange (resin) column chromatography, following the previous report.
1) Nineteen kinds of amino acid including β-Alanine and an unknown spot were confirmed.
2) The TCA soluble total amino acid markedly increased in each step of processing, and the amino acid content of peptide form increased more significantly than that free amino acid, in which Lys, Asp and Glu contents were high. In the commercial natto products the similiar trend was indicated.
3) During natto processing the ratios of amino acid liberation (ratio of free amino acid present to total amino acid) gradually decreased, and in commercial natto products the value was higher than the others. The ratios of liberation with each amino acid were markedly low with Cys, high in Try and Tyr in all the samples tested.
4) The Asp and Glu contents in the total amino acids and peptides as well as the ratios of Asp and Glu liberation suggested that in the commercial strains for natto manufacture the Asp liberation capability is apparently greater that for Glu, and in Bacillus natto No. 6 vice versa.
